GVRP
Introduction
General Operation
When GVRP is enabled on a switch, the VID for any static VLANs configured
on the switch is advertised (using BPDUs—Bridge Protocol Data Units) out
all ports, regardless of whether a port is up or assigned to any particular VLAN.
A GVRP-aware port on another device that receives the advertisements over
a link can dynamically join the advertised VLAN.
A dynamic VLAN (that is, a VLAN learned through GVRP) is tagged on the port
on which it was learned. Also, a GVRP-enabled port can forward an advertise
ment for a VLAN it learned about from other ports on the same switch (internal
source), but the forwarding port will not itself join that VLAN until an adver
tisement for that VLAN is received through a link from another device (exter
nal source) on that specific port
Operating Note: When a GVRP-aware port on a switch learns a VID through GVRP from another device, the switch begins
advertising that VID out all of its ports except the port on which the VID was learned.
Core switch with static
VLANs (VID= 1, 2, & 3). Port 2
is a member of VIDs 1, 2, & 3.
1.
Port 2 advertises VIDs 1, 2,
& 3.
Switch 1
GVRP On
2
11.
Port 2 receives
advertisement of VID 3. (Port ment of VID 3 AND becomes ment of VID 3 AND becomes
2 is already statically
configured for VID 3.)
Figure 3-1. Example of Forwarding Advertisements and Dynamic Joining
3-4
2.
Port 1 receives advertise
ment of VIDs 1, 2, & 3 AND
becomes a member of VIDs becomes a member of VIDs
1, 2, & 3.
3.
Port 3 advertises VIDs 1, 2,
& 3, but port 3 is NOT a
member of VIDs 1, 2, & 3 at
this point.
Switch 2
GVRP On
3
1
9.
Port 3 receives advertise
a member of VID 3. (Still not a member of VID 3. (Still not
a member of VIDs 1 & 2.)
10.
Port 1 advertises VID 3.
4.
Port 4 receives advertise
ment of VIDs 1, 2, & 3 AND
1, 2, & 3.
5.
Port 5 advertises VIDs 1, 2,
& 3, but port 5 is NOT a
member of VIDs 1, 2, & 3 at
this point.
Switch 3
GVRP On
4
5
7.
Port 5 receives advertise
a member of VIDs 1 & 2.)
8.
Port 4 advertises VID 3.
Port 6 is statically configured
to be a member of VID 3.
Static VLAN con
figured End Device
(NIC or switch) with
GVRP On
6
6.
Port 6 advertises VID 3.